It's easy to think that all tables of information is the same and has the same needs, but as soon as you dive into the details many needs merge.

Lets start with these two;

1. You need to find and show a list of something out of tens of thousands in the database
2. You need to show records related to something you already have on screen

For 1 you need to use SQL (oclPS) to find only as subset of rows and load only these into memory

For 2 you might be able to load all into the server memory, but it's often to many rows to send all of them to the client

Let's continue complicating the picture,